/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.tuscany.sca.contribution.resolver;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
/**
* The default implementation of a model resolver extension point.
*
* @version $Rev: 910841 $ $Date: 2010-02-17 06:48:29 +0000 (Wed, 17 Feb 2010) $
*/
public class DefaultModelResolverExtensionPoint implements ModelResolverExtensionPoint {
private final Map<Class<?>, Class<? extends ModelResolver>> resolvers = new HashMap<Class<?>, Class<? extends ModelResolver>>();
private Map<String, ServiceDeclaration> loadedResolvers;
private ExtensionPointRegistry registry;
/**
* Constructs a new DefaultModelResolverExtensionPoint.
*/
public DefaultModelResolverExtensionPoint(ExtensionPointRegistry registry) {
this.registry = registry;
}
public void addResolver(Class<?> modelType, Class<? extends ModelResolver> resolver) {
resolvers.put(modelType, resolver);
}
public void removeResolver(Class<?> modelType) {
resolvers.remove(modelType);
}
@SuppressWarnings("unchecked")
public Class<? extends ModelResolver> getResolver(Class<?> modelType) {
loadModelResolvers();
Class<?>[] classes = modelType.getInterfaces();
for (Class<?> c : classes) {
Class<? extends ModelResolver> resolver = resolvers.get(c);
if (resolver == null) {
ServiceDeclaration resolverClass = loadedResolvers.get(c.getName());
if (resolverClass != null) {
try {
return (Class<? extends ModelResolver>)resolverClass.loadClass();
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException(e);
}
}
} else {
return resolver;
}
}
Class<? extends ModelResolver > resolver = resolvers.get(modelType);
if (resolver == null) {
ServiceDeclaration resolverClass = loadedResolvers.get(modelType.getName());
if (resolverClass != null) {
try {
return (Class<? extends ModelResolver>)resolverClass.loadClass();
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException(e);
}
}
}
return resolver;
}
/**
* Dynamically load model resolvers declared under META-INF/services
*/
private synchronized void loadModelResolvers() {
if (loadedResolvers != null)
return;
loadedResolvers = new HashMap<String, ServiceDeclaration>();
// Get the model resolver service declarations
Collection<ServiceDeclaration> modelResolverDeclarations;
try {
modelResolverDeclarations = registry.getServiceDiscovery().getServiceDeclarations(ModelResolver.class, true);
} catch (IOException e) {
throw new IllegalStateException(e);
}
List<ServiceDeclaration> list = new ArrayList<ServiceDeclaration>(modelResolverDeclarations);
// Load model resolvers, add entries from lower ranking to higher ranking so that higher ranking ones override
// the map
for (int i = list.size() - 1; i >= 0; i--) {
ServiceDeclaration modelResolverDeclaration = list.get(i);
Map<String, String> attributes = modelResolverDeclaration.getAttributes();
String model = attributes.get("model");
// The model can be a list of interfaces so that one model resolver can be used
// to resolve different types of models
if (model != null) {
StringTokenizer tokenizer = new StringTokenizer(model);
while (tokenizer.hasMoreTokens()) {
String key = tokenizer.nextToken();
loadedResolvers.put(key, modelResolverDeclaration);
}
}
}
}
}